There is a need to determine whether or not a driver is in attentive or falls asleep at the wheel while driving. For this purpose, a process is performed to read a face orientation or an eye state from the driver's face image and raise an alarm as needed. However, a vehicle moves and a light environment to capture the driver varies accordingly. As a result, a face image is too dark or causes halation. Accurately analyzing the face image is difficult, making it impossible to accurately read face states (e.g., face orientation, visual line direction, and eye opening or closing state). Such a condition, if continued, may make it difficult to appropriately raise an alarm.
Therefore, there is proposed a camera-equipped portable information terminal apparatus (see Patent Literature 1) that can identify the commercial power frequency used for a region and automatically prevent a flicker from occurring.
There is proposed a camera (see Patent Literature 2) that varies the frame rate of an image capturing apparatus according to an illumination frequency or brightness and thereby enables to prevent a flicker and adjust the amount of light without using an electronic shutter.
There is proposed an onboard image processing apparatus (see Patent Literature 3) capable of providing an appropriate alarm regardless of changes in a light environment to capture a driver.
There is proposed an image processing apparatus (see Patent Literature 4) capable of acquiring a clearly captured image regardless of light and dark around an object to be captured.